MADISON, Wis. (AP) – The Wisconsin Department of Natural Resources’ headquarters in Madison is back open after a flood sent workers home Tuesday afternoon and shuttered the building for half a day. The state Department of Administration said Wednesday the DNR has returned to normal operations and cleanup from the flood is nearly complete. The DOA reports that the building is dry, all pipes have pressure, affected work stations have been cleaned, and the heating system is working. A cost estimate for how much damage was caused won’t be known for weeks, but DOA says work stations and computer equipment suffered only minor damage. The DOA statement says the flood appears to have been caused by a system failure that resulted in cold air being pulled in, causing the pipes to freeze and burst.